The exemplary embodiments disclosed herein relate to methods of manufacturing nonvolatile memory devices, and more particularly, to methods of manufacturing nonvolatile memory devices having a three-dimensional structure capable of improving reliability, and nonvolatile memory devices manufactured by the methods.
Generally, nonvolatile memory devices can electrically erase and program data and can retain their stored data even when their power supplies are interrupted. The use of nonvolatile memory devices has increased dramatically in various fields.
Nonvolatile memory devices include various types of memory cell structures and are classified as NAND type memory devices and NOR type memory devices, depending on the memory cell array structure of the device. NAND type memory devices and NOR type memory devices have the advantages of high integration and high speed, respectively.
In particular, since a NAND type nonvolatile memory device has a cell string structure connecting a plurality of memory cell transistors in series, it is advantageous in high integration. Also, since a NAND type nonvolatile memory device adopts an operation method of changing data stored in a plurality of memory cell transistors at the same time, a speed of updating data is much faster than that of a NOR type nonvolatile memory device. Because of high integration and a high data update speed, a NAND type nonvolatile memory device is mainly used in portable electronic devices which need mass storage devices, such as digital cameras, MP3 players or the like. Studies have been performed so as to expedite and raise the advantages of a NAND type nonvolatile memory device. A NAND type nonvolatile memory device having a three-dimensional structure is being developed.
Nonvolatile memory devices can be classified as floating gate type nonvolatile memory devices or charge trap nonvolatile memory devices, depending on the type of a memory storage layer constituting a unit cell. Since the charge trap nonvolatile memory devices can realize a low power supply, a low voltage and high integration, development of the charge trap nonvolatile memory devices increases.